Mobile communications networks are in the process of offering increasingly sophisticated capabilities associated with the motion and/or position location sensing of a mobile device. New software applications, such as, for example, those related to personal productivity, collaborative communications, social networking, and/or data acquisition, may utilize motion and/or position sensors to provide new features and services to consumers. Moreover, some regulatory requirements of various jurisdictions may require a network operator to report the location of a mobile device when the mobile device places a call to an emergency service, such as a 911 call in the United States.
In conventional digital cellular networks, position location capability can be provided by Advanced Forward Link Trilateration (AFLT). AFLT may compute the position of a wireless device from the wireless device's measured time of arrival of radio signals transmitted from a plurality of base stations. Improvements to AFLT have been realized by utilizing hybrid position location techniques, where the mobile device may employ a Satellite Positioning System (SPS) receiver. The SPS receiver may provide position information independent of the information derived from the signals transmitted by the base stations. Moreover, position accuracy can be improved by combining measurements derived from both SPS and AFLT systems using conventional techniques. Additionally, with the increased proliferation of micro electro-mechanical systems (MEMS), small, on-board sensors may be used to provide additional relative position, velocity, acceleration and/or orientation information. However, position location techniques based upon signals provided by SPS and/or cellular base stations may encounter difficulties when the mobile device is operating within a building and/or within urban environments. In such situations, multipath and/or degraded signal strength can significantly reduce position accuracy, and can slow the “time-to-fix” to unacceptably long time periods.
Such shortcomings of SPS and cellular positioning may be overcome by exploiting signals used existing wireless data networks, such as Wi-Fi (e.g., Institute of Electrical and Electronics Engineers (IEEE) 802.11x standards) and/or WiMAX (IEEE 802.16), and having elements within the network infrastructure derive position information of the mobile device. Techniques used in such wireless data networks may exploit round trip time (RTT) and/or signal strength measurements (RSSI) derived from signals utilized within these networks. Utilizing such measurement techniques to accurately determine position typically involves knowledge of the configuration of various elements within the network, such as, for example, the location of the wireless access points/femtocells, etc.
In practice, some network elements used for position determination may not be properly configured, and such misconfigurations could adversely impact the accuracy of the determined position solution. For example, if wireless access point is moved to a different location and the location it reports is not updated, positions determined using the old location of the wireless access point may be unacceptably inaccurate.
Accordingly, it may be desirable to implement calibration techniques which can update and/or compensate for improperly configured network elements to maintain position determination accuracy, while reducing costly post-deployment efforts for network infrastructure maintenance.